The Intel Graphics Media Accelerator, or GMA, is Intel's current line of integrated graphics processors built into various motherboard chipsets.These integrated graphics products allow a computer to be built without a separate graphics card, which can reduce cost, power consumption and noise. They are commonly found on low-priced notebook and desktop computers as well as business computers, which do not need high levels of graphics capability. 90% of all PCs sold have integrated graphics. They rely on the computer's main memory for storage, which imposes a performance penalty, as both the CPU and GPU have to access memory over the same bus.

In theory the more ram you have, the more will the gpu use when needed. But there are limiting factors. For 4gb of ram i presume gpu will be allowed to "take" 1.7gb for usage when needed, but only when needed. Don't hold my word tho, i'm not good with integrated gpus

It means your chipset comes with the Intel GMA X4500. The performance depends on the chipset too but yes you could say you will have the performance of the Intel GMA X4500. However, it can be either worse or better depending on the chipset.